1. Field of the Invention
The present invention pertains to the art of dishwashers and, more particularly, to a control system for a multi-compartment dishwasher.
2. Discussion of the Prior Art
In general, multi-compartment dishwashers are known in the art. Typically, a multi-compartment dishwasher includes multiple drawers or pull-out washing chambers slidably mounted in a cabinet. Of course there are also examples of multi-compartment dishwashers that combine a pull-out washing chamber with a conventional type compartment. Ordinarily, a dish rack is provided within each washing chamber to support dishware and the like during a washing operation. In most multi-compartment dishwashers, a washing operation can be performed in either one or both of the washing chambers.
Typically, household dishwashers are powered by a dedicated 15 amp circuit. When both compartments of a multi-compartment dishwasher are operating simultaneously, power must be shared between the washing chambers. Generally, power sharing between the washing chambers does not pose any problems. Wash pumps, drain pumps and control elements do not, in most cases, have high power requirements. In contrast, heating units for heating the washing fluid do have a high power requirement. Simultaneous operation of the heating units could cause the dishwasher to exceed the 15 amp circuit limit.
In order to ensure that a multi-compartment dishwasher doesn't exceed the 15 amp circuit limit, manufacturers employ a control system that staggers operation of the washing chambers. That is, the control system delays activating one of the washing chambers until another of the washing chambers reaches a predetermined point in the washing operation. Staggering operation of the chambers ensures that the heating units are not operated at the same time. However, in order to achieve and/or time the desired staggered operation, each washing chamber requires special programming and/or dedicated electrical circuitry.
In addition to sharing power, some multi-compartment dishwashers are designed to share a common water supply. That is, the dishwasher includes a single water inlet valve that is bifurcated to feed each washing chamber during simultaneous operation. The valve is operated to fill one, then the other of the washing chambers. Of course, sharing a single fill valve requires additional programming for the control system.
In general, when sharing resources between multiple washing chambers, one chamber must be dominant over the other. More specifically, one chamber must be designated as a primary chamber and the other as a secondary chamber. The primary chamber receives initial access to system resources, while the secondary chamber must wait for the system resources to be allocated. In order to achieve this hierarchical relationship, even more programming and additional extensive wiring/circuitry is necessary.
Based on the above, there still exists a need for a control system for a multi-compartment dishwasher that can designate one compartment as being primary and other compartment(s) as being secondary without requiring specific controllers, control programming or extensive wiring/circuitry. That is, there exists a need for a universal controller that can be externally assigned as a primary or secondary controller.